CAJ | 학술논문

为探讨循环荷载作用下夯实水泥土圆柱形桩与夯实水泥土楔形桩复合地基工作性状的差异，通过室内模型试验，并在桩顶及桩周土表面埋设微型土压力盒，进行循环荷载下夯实水泥土圆柱形桩和楔形桩的4桩复合地基及单纯软土地基工作性状对比试验，探讨循环应力比和加载周数对夯实水泥土圆柱形桩和楔形桩复合地基永久沉降、桩-土应力比的影响规律。研究软土地基加固方法对永久沉降和桩-土应力比的影响，揭示了循环应力比与桩-土应力比的关系。研究结果表明：采用夯实水泥土桩加固软土地基，能提高地基的临界循环应力比，增强地基抵抗循环荷载的能力；在相同的加荷周数和循环应力比的加载条件下，采用夯实水泥土楔形桩加固软土地基对降低地基永久沉降的效果比采用夯实水泥土圆柱形桩的效果要好，且楔形桩的楔角越大，降低永久沉降的效果越明显。循环应力比越大，桩-土应力比越大；桩-土应力比随楔形桩楔角的增大而增大，随加载周数的增加而降低，并存在一临界加载周数；当加载周数小于临界周数时，桩-土应力比随加载周数迅速降低；当加载周数超过临界周数时，桩-土应力比几乎不随加载周数的变化而变化。
위탐토순배하재작용하항실수니토원주형장여항실수니토설형장복합지기공작성상적차이，통과실내모형시험，병재장정급장주토표면매설미형토압력합，진행순배하재하항실수니토원주형장화설형장적4장복합지기급단순연토지기공작성상대비시험，탐토순배응력비화가재주수대항실수니토원주형장화설형장복합지기영구침강、장-토응력비적영향규률。연구연토지기가고방법대영구침강화장-토응력비적영향，게시료순배응력비여장-토응력비적관계。연구결과표명：채용항실수니토장가고연토지기，능제고지기적림계순배응력비，증강지기저항순배하재적능력；재상동적가하주수화순배응력비적가재조건하，채용항실수니토설형장가고연토지기대강저지기영구침강적효과비채용항실수니토원주형장적효과요호，차설형장적설각월대，강저영구침강적효과월명현。순배응력비월대，장-토응력비월대；장-토응력비수설형장설각적증대이증대，수가재주수적증가이강저，병존재일림계가재주수；당가재주수소우림계주수시，장-토응력비수가재주수신속강저；당가재주수초과림계주수시，장-토응력비궤호불수가재주수적변화이변화。
To study difference for the work behavior of the composite foundation with rammed cement-soil column and tapered piles under cyclic load, based on the indoor model tests, and installing the miniature soil pressure boxes on the pile-top and the soil surface, the contrast model tests of working properties for the composite foundation with 4 rammed cement-soil column piles and with 4 rammed cement-soil tapered piles, and the soft foundation are performed in laboratory, respectively. The influence laws of the cyclic stress ratio and the number of cyclic load on the permanent settlement and the pile-soil stress ratio of the composite foundation with rammed cement-soil column and tapered piles are explored. The influence of the reinforcing methods on the permanent settlement and the pile-soil stress ratio are researched in the soft foundation. The relation of the cyclic stress ratio and the pile-soil stress ratio is revealed. The results of the study show that the critical cyclic stress ratio and the ability to resist cyclic load of the foundation may be enhanced by the composite foundation with rammed cement-soil piles. In the same loading conditions for the same number of cyclic load and the same cyclic stress ratio, the effect that the permanent settlement is decreased by the composite foundation with rammed cement-soil tapered piles is better than that by rammed cement-soil column piles. The greater the wedge angle is, the better the effect is. The greater the cyclic stress ratio is, the greater the pile-soil stress ratio is. The pile-soil stress ratio increases as the wedge angle of the tapered pile increasing;but that decreases as the number of cyclic load increasing. There is a critical number of cyclic load. When the number of loading cycle is less than the critical number of cyclic load, the pile-soil stress ratio decreases rapidly as the number of cyclic load increasing. When the number of loading cycle is more than the critical number of cyclic load, the pile-soil stress ratio almost has no change as the number of cyclic load increasing.